Over a 9-month period 3424 patients with a head injury were examined in the Accident and Emergency Department of Monklands District General Hospital. Casualty officers diagnosed 66 fractures of the skull on radiographs but 27 of these were subsequently reported by a radiologist as not being fractures. Of the 45 fractures reported by the radiologist 6 had been missed by the casualty officer. This study demonstrates the performance of junior medical staff who have no formal training in radiology. It emphasizes the need to instruct such staff when they are assigned to work in accident and emergency departments.